There are two basic types of lawn sprinkler systems on the market. The first type of system uses above-ground hoses that are attached to a water supply and to a portable sprinkler. This system allows the user to freely place the sprinkler in any position on the lawn. To entirely water a lawn area, a user must move the hose and sprinkler to different locations. This free moving system offers the user a number of advantages. 1) The materials needed, i.e. a hose and a sprinkler, are readily available on the market, and 2) the variety of sprinklers available offer the user different options of expense and area coverage depending on the size and shape of the area to be covered. This system has disadvantages, it can be time consuming for the user as the system must be set up each time it is used and the hose and sprinkler must be moved and readjusted a number of times before an entire area is adequately watered. Furthermore, the act of watering the lawn can be messy as the user must walk through wet grass and readjust the sprinkler, with the risk of getting wet, each time it is moved.
The second type of system does not require the user to move hoses and sprinklers because the entire system is fixed underground. This fixed system has specially designed sprinklers that are installed in the ground. The sprinkler in the underground system is held in the ground by a canister when it is not in use. Underground pipes are connected to the canisters and a water supply. According to U.S. Pat. No. 4,892,252, when the water enters the canister, the pressure differential in the canister and sprinkler cause the sprinkler to pop-up out of the canister. After the sprinkler has popped-up, water will issue forth from the sprinkler outlet and water the area. When the water stops flowing through the system the sprinkler returns to its position within the canister by way of a spring or gravity. The sprinkler can also be of the type disclosed in U.S. Pat. No. 4,353,506 or an externally driven sprinkler.
Because the system is positionally fixed, it is simpler to operate and is far less time consuming. Often an underground system is attached to a timer that, on a regular basis, automatically will turn the water supply on and off. Consequently, the user is not required to spend the same amount of time to water the yard as in the first system and is not subject to the same sort of physical mess.
On the other hand, the underground system presents other problems for the user. Installation and maintenance is expensive as well as time consuming and disruptive. Because the system is installed in the ground, a system scheme must be specially designed for the area to be watered. Once a system is designed, the yard must be dug up to install the system. The yard also must be dug up to make any repairs to the sprinklers and the pipes. Furthermore, because the system is fixed, it is difficult to make modifications once it is installed. Much of this work is often performed by underground sprinkler system professionals instead of home owners or the like. In summary, the system can be difficult and expensive to maintain.
Because of the construction of the sprinkler and canister revealed in the prior art, it has not been possible to have a simple, inexpensive sprinkler system that can be retained below the ground when not in use.
As is evident from the above description, there are a number of limitations to the two prior art systems. The free moving system tends to be messy and time consuming, while the fixed system is expensive and difficult to install and repair. The difficulties suggested in the proceeding are not intended to be exhaustive but rather ones that tend to demonstrate some limitations of the two systems. Other noteworthy problems may also exist; however, the disadvantages presented above should be sufficient to illustrate that sprinkler systems known in the past will admit to worthwhile improvements.